Sciencegal, If I had soil like you describe I would look into something like hay/strawbale gardening. It is cheaper than making raised beds and you won't be wasting money on fertilizer and water that will quickly wash away. It will also help improve the soil underneath.
Some things to think about.
In a discussion at another site today the conversation was about the effect of culture on flavor. One example was a notible difference in flavor between tomatoes grown with manure compost vs composted leaves. The person growing with manure said the neighbor's tomatoes tasted much better, the only difference being the leaf vs manure compost. The second example was between two gardeners in a community garden wondering why one's peas were much sweeter than the other's. The only differences being that the plot with poorer flavor used more water and boxed organic fertilize, while the better flavored garden used less water and home made compost.
Now on the subject of nitrates in the soil. A dense cover crop of alfalfa tilled in to "organically fertilize" a corn field will produce two times the amount of nitrates below the root line than will a traditionally fertilized corn field (corn is heavily fertilized). So the cover crop used to fertilize a corn field will cause twice as much ground water contamination than the optimal application of synthetic fertilizer. Nitrates in the drinking water can be toxic to infants.
As far as synthetic fertilizers poisoning the soil fauna, mushroom growers use such high quantities of synthetic fertilizers (potash, ammonium nitrate, urea) in the compost used to grow the mushrooms that even after the mushroms are done with it the compost is so high in salts that it can burn plant seedlings, so obviously the fertilizers are not directy harming the soil fauna.
Traditional farming practices do little to add organic matter to the soil and synthetic fertilizers increase growth of both plants and microbes, but unlike the plants the microbes need a carbon source (organic matter) for energy (food). The fast multiplying soil bacteria decompose the soil organic matter quickly and out compete (basically starve out) the fungal community. You could alter the soil microbial community in the same way by using bags of preformulated "organic" fertilizer (or the liquid stuff used for organic hydroponics). Adding organic matter in the way of compost or manure to give the fungi a carbon source is the key factor in organic farming being better for the soil than traditional farming.
Lastly, about nutritional benefits of organic vs traditional vegetables. The vast majority of scientific research shows no significant difference in nutritional quality between organic and traditional produce (just as many studies go one way as the other, or break even). This does not make much sense when thinking about micronutrient depleated "traditional soils" until you understand how organic farming practices can easily shift the balance in soil nutrient levels in such a way that plant physiology is affected. Namely, repeated applications of manure to provide the needed nitrogen builds up potassium levels in the soil (a common problem), and the shifted ratio of calcium to potassium decreases the nutritional quality of the produce. You can always argue whether protein to carbohydrate ratio or anti oxidant levels etc define nutritional quality if you want to promote one farming method over the other.
Of course there is the question of pesticide use on traditional farms, and varieties grown for productivity, shipping and shelf life, which will favor organically grown produce for flavor and safety, but that is a different arguement.
We could just as easily be in a heated discussion (using the same arguements) over which is better, container growing or inground growing. Consider the following for container growing: evil plastic container, plastic bags of processed potting mix, petroleum used for manufacture and transport, nitrate explosives used to mine the dolomitic lime used to buffer pH of the mix, the environmental damage caused by that mining, petroleum used to crush it, water conservation issues, flavor, production... But for some reason "organic vs chemical" polarizes/opinionates people like nothing short of religion and politics.